The program has the following aims: (1) Determination of the primary structure of bovine pancreatic carboxypeptidase B. The action of trypsin on the maleylated, S-aminoethyl protein generates a series of relatively large fragments. These have been separated and their sequences are being determined. (2) Investigations on the structure of the three heterosaccharide side chains in porcine ribonuclease will be continued by application of permethylation procedures. (3) The influence of the heterosaccharide side chains in porcine ribonuclease on the conformational stability of the protein is being investigated by measurements of the rate of refolding of the reduced, completely denatured protein, by studies of the thermal transition and by analysis of the acid and alkaline ultraviolet difference spectra. (4) Attempts will also be made to develop information concerning the specificity site in bovine carboxypeptidase B by application of site-selective reagents.